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Use case · 2 minutes

How to shrink a PDF to fit an email attachment limit

Get a 40 MB scan under Gmail's 25 MB or Outlook's ~20 MB cap — without it turning to mush.

For: Anyone bouncing off a 'file too large' error sending invoices, scans, decks, or contracts by email
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STEP BY STEP

The workflow

1
Check what you're actually dealing with
Run PDF Inspector first. If the file is huge because it's a 300-page scan, you'll compress differently than if it's a 6-page deck with one enormous embedded image. Know the page count and where the weight is.
Open Page Count
2
Compress at the right quality level
Start with Balanced. Most scanned and image-heavy PDFs drop 60-80% with no visible difference at screen and normal print sizes. If it's still over the limit, step up to Strong; if the text must stay razor-sharp for print, use Light and pair it with the next step.
Open Compress PDF
3
If it's still too big, split instead of crushing
A 250-page contract won't fit any cap at readable quality. Split it into 'Part 1 / Part 2' by page range and send two clean emails — far better than a single unreadable file. Recipients prefer two legible halves to one blurry whole.
Open Split PDF
WHY IT MATTERS

The case for doing this

Email size limits are the single most common reason a PDF won't send: Gmail caps attachments at 25 MB, Outlook.com at about 20 MB, and many corporate mail servers at 10 MB or less. The instinct is to crush quality until it fits, but over-compression makes text fuzzy and tables unreadable — which defeats the purpose of sending the document at all. The right move is to compress intelligently (most of a PDF's weight is rescaleable images, not text) and, only when a file is genuinely too large at acceptable quality, to split it. Compress PDF runs server-side with Ghostscript, keeps text selectable and searchable, and falls back to your original if compression wouldn't actually help — so you never ship a 'compressed' file that's somehow bigger. Doing this in two minutes beats uploading to a sketchy 'free' site that watermarks your invoice or emails you forever after.

COMMON MISTAKES

What to avoid

Going straight to maximum compression
Strong compression on a text-only PDF gains you almost nothing and can soften the type. Balanced is the right default; only escalate if you're still over the cap.
Compressing a file that's mostly text
If the weight is text and vectors, compression has little to work with — you need to split, not crush. PDF Inspector tells you which case you're in before you waste a pass.
Forgetting the recipient's limit, not yours
Your provider may allow 25 MB but a corporate recipient's gateway may reject anything over 10 MB silently. When in doubt, aim under 10 MB or use a shared link.
TIPS FOR THE BEST RESULTS

What works

Name the output so you can tell versions apart
invoice-2026-03-compressed.pdf keeps the email-ready copy distinct from your full-resolution master.
Compress AFTER merging, not before
If you're combining several scans, merge first and compress the single result once — compressing each part then merging re-bloats the file.
Everything runs in your browser or our server, watermark-free
Compress PDF is free and unlimited, adds no watermark, and never stores your file — important when the attachment is a contract or an invoice.
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FAQ

Questions about this workflow

Text stays vector-sharp at Balanced and Light — only embedded images are downsampled. Strong can soften scanned (image-based) text, so use it only when you must fit a hard cap.

Try the workflow on a real PDF

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